Abstract

It has been reported that a preparation obtained from prothlalli of the fern species Anemia phyllitidis controls antheridium formation in this species. If this same preparation is applied at the spore stage it induces a physiological state antagonistic to antheridium formation. The inhibitory state is inducible only at a very early stage of development, but, once induced, it remains manifest at much later stages. Quite possibly, the inhibitory state arises in response to the factor that induces formation of anitlheridia. The inhibitory state may have an important function in fern development.